Tablet shuts off with out warning.

Ok so I have this tablet for a couple of years now and has been doing this the day I got it.

I put the tablet on the charger and charged it full. If the screen is off it will only use 1 or 2% for the whole day.
And when the screen is on it seems to discharge normally. But it can be using it for about a hour or so and when the tablet gets around 60-30% it will say battery dead then shut down. Other times it will just shut off without warning. And when it does, the battery is actually dead.

I changed the battery a couple of days ago and it still does the same thing. Any suggestions?